By MIKE LEWIS, SEATTLE POST-INTELLIGENCER REPORTER

Updated 10:00 pm, Wednesday, October 13, 2004

Mount St. Helens continued to reveal its inner self yesterday as additional glowing lava pushed to the surface in the volcano's crater.

The hot rocks -- incandescent and solid, not ropy, red liquid lava -- added a sizable "fin," or wall of stone, to a new, growing dome in the crater. The lava is the source of regular steam and ash plumes seen for miles around the newly awakened volcano.

The uplifting -- the geologists tracking it called it dome building -- could continue for weeks, months or years. Geologists said that although the expansion appears steady at this point -- the volcano remains at a moderate, Level 2 eruption alert -- the process is not completely understood, and surprises could be in store.

"We know conditions can change very rapidly," said Tina Neal of the U.S. Geological Survey. Neal, speaking from the Cascades Volcano Observatory in Vancouver, Wash., said yesterday that there is no current indication that a large explosion is imminent.

Newly placed instruments designed to track the gases and subsurface blisters that indicate rising pressure show no such buildup so far, she said. Moreover, she added, gas appears to be venting pretty freely.

Addressing specific concerns that the mountain's south flank could explode the way the north side did in 1980, Neal said, "We absolutely have no evidence of any movement on any flank."

Geologists described the rapid dome building within the mile-wide crater as impressive. The glowing, 1,110-degree-Fahrenheit fin pushed up from below the surface and is between 60 and 90 feet tall and almost 200 feet wide, as estimated from flyovers.

Seismic activity remains low, with earthquakes steady but not surpassing levels seen as recently as one week ago when the mountain reached a Level 3 alert status, which meant that an eruption posing risks to life and property was considered imminent.

St. Helens began quivering Sept. 23. Within a week, geologists and authorities with the U.S. Forest Service evacuated the Johnston Ridge Observatory near the crater and closed high mountain trails.

Since then, St. Helens has regularly spewed steam and ash but has posed no unusual hazard to nearby residents or aircraft. The blast May 18, 1980, leveled miles of forests, triggered massive mudflows and landslides and killed 57 people. Soon after the eruption, magma began pushing up a lava dome on the crater's floor. The new lava dome is forming just behind that existing dome.

The vented gases help geologists determine the pressure's depth and the likelihood of an explosive eruption.

Scientists also plan to use a remote, unmanned drone plane for near-dome work. The 22-pound plane, dubbed the "Silver Fox," is expected to face steady streams of turbulence, updrafts, downdrafts and wind bursts, said Ned White, a drone pilot.